W70B and WH62 headset

[DavidVF]

I noticed in the latest W70B firmware 146.85.0.40, the W70B now supports the DECT cordless headsets:

Quote:Supported new headsets WH6X/WH6X Portable/WHM621 with
Charging Cable/WHD622 with Charging Cable/WHM631 with Charging
Cable.
Description: The Yealink W70B supports the registration of headset endpoints and configures the SIP account for them. They can be registered and used on
W70B alone or bound with other handsets. After binding, you can push/retrieve
the calls between the handset and the headset. The headsets also support
Intercom calls and OTA upgrading.

I've managed to pair a WH62 to the W70B but I've been unable to work out how to bind a headset to a particular handset, has anyone else figured this out?

kr, David